What To Do After Replacing Crankshaft Sensor [Explained]

Replacing the crankshaft sensor becomes essential when it goes bad and causes performance issues. But if you’ve never replaced it before, you can naturally wonder what to do after replacing the crankshaft sensor in your car.

There are several problems you can face if you don’t install it the correct way and reset it after replacing it. The two main things you want to make sure that you do after replacing the sensor are to recheck whether you’ve installed it correctly and reset it so that the ECU can relearn its position.

what to do after replacing crankshaft sensor

You’ll learn all about how to do these two things in detail by following this guide. Without further ado, let’s delve into it!

What To Do After Replacing Crankshaft Sensor [Know A-Z]

The most common problems after replacing crankshaft position sensor in your car are either your car won’t start, stall, or the check engine light will be on.

You’ll learn all about what causes these issues and how you can fix them in this section. This guide will give you a clear idea of all the important things you should take care of after replacing the crankshaft sensor.

Note: You can also read how to fix oil on the Camshaft Position Sensor.

Make Sure The Crankshaft Position Sensor Was Installed Correctly

If you’re having a tough time starting your car after replacing your crankshaft position sensor, chances are that you’ve not installed it correctly.

So, the first thing you need to make sure of is whether they’re installed in the right manner or not. If not, you need to address the issue and that’ll solve your problem.

Let’s take a look at the right way to replace a crankshaft sensor. Compare it to your installation process and retrace your steps. If you made a mistake, rectify it and that should solve your problem.

How To Replace Crankshaft Position Sensor

Before replacing the crankshaft position sensor, it’s a good idea to confirm that you have a bad crankshaft position in the first place. You can check it by connecting a code scanner to your car. If you have a P0335 error code that looks like this, you have a bad crankshaft sensor.

The crankshaft position sensor is easy to replace. You can refer to your owner’s manual to know its location but it’s located between the engine and the transmission in most modern cars. You can follow these steps to replace the crankshaft sensor:

  • Turn off the engine and wait for it to cool down.
  • Disconnect the negative terminal of the battery as the crankshaft position sensor is an electrical component.
  • Locate the crankshaft position sensor.
  • Loosen the retaining bolt holding the crankshaft sensor in place.
  • You’ll need to use a short extension to remove it as there’ll be little space to work on it.
  • Once the retaining bolt is loose, you can use your fingers to remove it.
  • Disconnect the electrical connector connected to the sensor.
  • Pull out the old sensor from the engine.
  • Add some oil to the new crankshaft sensor and the O-ring.
  • Put the new sensor in place of the old one.

Fitting the new sensor in its place is the reverse of the removal process. If your car is not starting after you’ve changed the crankshaft sensor, maybe you forgot to reconnect the battery and that’s causing the issue.

Look at each of the steps carefully and try to identify if you made any errors. If you did, fix them. A lot of people mistake the camshaft sensor for the crankshaft sensor as they look identical.

But remember that the camshaft sensor is typically located at the top of the engine while the crankshaft position sensor is located at the bottom. Changing one instead of the other will not solve your problem.

Even if you didn’t mess up the installation process, the connectors can become corroded, there may be wiring issues or the crankshaft sensor can go bad again. All of these things will prevent the car from starting. Check these things again and make sure everything is okay before moving on to the next step.

Reset The Crankshaft Position Sensor

You may think that resetting the crankshaft position sensor is not a necessary step when you’re done with the replacement. But do you know what happens if you don’t relearn the crankshaft position sensor after replacing it?

You’ll find the check engine light still on after replacing the crankshaft position sensor or the car won’t start in a few cases if you don’t reset it. You can reset the crankshaft sensor with or without a scanner.

How To Reset Crankshaft Position Sensor With Scanner

If you have a scanner available, it’s a good idea to check for trouble codes anyways after replacing the crankshaft sensor. Because even if the car run fines without resetting the sensor, any misfiring will go undetected by the ECU unless it has been reset.

Resetting it alerts the system when there’s a misfire and brings on the check engine light when necessary. But if you’re facing your car won’t start issue or seeing a check engine light already, follow these steps to reset it:

  • Connect the code scanner to your car’s computer.
  • All the trouble codes from the previously faulty sensor should go away.
  • You should see a DTC P1336 CKP Variation Not Learned signal.
  • Set the brake while blocking the drive wheels with the hood closed.
  • Start the engine and make sure the engine oil and coolant are at optimal temperature.
  • Shut down the engine for a few seconds.
  • Choose CASE Learn on your scanner to make the sensor ready for the learning procedure.
  • Make sure the transmission is in park.
  • Start the engine, press the brakes, and hold the pedal firmly.
  • When the engine goes to the idle state, you can check the Diagnostic Trouble Code or DTC P1336.
  • It’ll either indicate that the CASE is learned or not learned.
  • If it has learned the CASE, you’re done and the reset is complete.
  • If it hasn’t learned the case, check for further diagnostics.
  • Clear the trouble codes and restart the learning process again.

How To Reset Crankshaft Position Sensor Without Scanner

Not everyone will have a scan tool close to them to reset the crankshaft position sensor. There are two ways you can go about resetting it without a scanner.

Method 1 – Acceleration And Decelaraiton Cycles

In the first method of resetting the crankshaft position sensor without a scanner, you’ll be accelerating and deceleration the car at certain speeds. Here’s a breakdown of the method in easy steps:

  • Switch off all the accessories in your car.
  • Keep the temperature of the coolant and air temperature sensors close to each other.
  • Keep the engine idle in Neutral or Park position for at least two minutes.
  • Accelerate your car close to 55 mph at part throttle.
  • Keep up this speed for at least a few minutes so that the engine can reach its operating temperature.
  • Reduce the speed to 45 mph for a minute.
  • Conduct the same deceleration cycle for 25 seconds each without applying the brakes.
  • Come back to 45 mph in between those deceleration cycles for 15 seconds.
  • Accelerate your car to 55 mph again and drive at this speed for a few minutes.
  • Stop your car and set it at idle for a few minutes.

Completing all these steps carefully will reset the crankshaft position sensor without any scanner. But if this method is complicated for you, you can take a look at the second method.

Method 2 – Disconnecting The Battery

Many people wonder will disconnecting the battery reset the crankshaft sensor and the answer to that question is yes. Disconnecting the negative terminal of the battery and letting your car sit for at least one hour before you reconnect it will drain the power from all the electrical components in your car.

disconnecting the battery

That includes the ECU and it’ll lose its short-term memory. When the ECU loses its memory, it’ll relearn the position of the crankshaft sensor when you start your engine. This process is easy but the downside is that it can take a long time for all the electrical components to lose power.

Resetting the sensor should get rid of the check engine light if you had it on after replacing the crankshaft and the no-start issue as well. If the crankshaft position sensor itself is faulty, you’d have had trouble starting the vehicle or it would at least stall.


How does the crankshaft position sensor work?

The crankshaft sensor informs the ECU about the position of the engine. The ECU uses that information to fire the fuel injectors and the spark plugs at the right time.

How to fix a bad crankshaft sensor?

You don’t fix a bad crankshaft sensor, you just replace it. Crankshaft sensors are inexpensive as they only cost $15- $30 and you can replace them yourself.

What happens when the crankshaft sensor goes out?

The ECU won’t be able to detect the position of the crankshaft when it goes out. That’ll cause trouble starting the engine, poor acceleration, and reduced engine performance.

How long does it take to reset the crankshaft sensor?

If you’re using a scanner, it shouldn’t take you more than 10-15 minutes to reset the crankshaft sensor. But it can easily take you 45 minutes or even a few hours without a scanner.


It can be frustrating if your check engine light is on or your vehicle won’t start after replacing your crankshaft. But now you know exactly what to do after replacing the crankshaft sensor to prevent these issues from taking place.

We hope this guide will help you understand all you need to know about replacing crankshaft position sensors the right way. Leave a comment below if you have any more questions about crankshaft position sensors.

About John M

John contributed as a technical head at an automobile company just 2 years after his post-graduation in Automobile Engineering. He loves to lead a free life, so he left his job & started blogging. Now, he does research on every automotive problem, part & product and seeks a better solution & best products & shares his findings with his readers to help them as well as to minimize their struggle.

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